Quick answer: Diabetes insipidus – now often called arginine vasopressin deficiency or resistance – is a rare water-balance disorder in which the body cannot properly hold on to water, so the kidneys pass a lot of dilute urine and the person feels very thirsty. Despite the shared word “diabetes”, it has nothing to do with blood sugar and is not the same as diabetes mellitus (sugar diabetes). It is caused by a problem with a hormone called vasopressin (also known as ADH): either the body makes too little of it, or the kidneys do not respond to it. It is usually well managed with the care of an endocrinologist, and free access to water is essential.
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Because of its confusing name, diabetes insipidus is often mistaken for the far more common sugar diabetes. In fact the two conditions are unrelated. This guide explains what diabetes insipidus is, the symptoms to look out for, how it is diagnosed and treated in Singapore, and when to seek urgent help. It is general information and does not replace a proper assessment by a doctor.
What it is
Diabetes insipidus is a rare condition in which the body cannot properly balance its water. Normally a hormone called vasopressin (or antidiuretic hormone, ADH) tells the kidneys to conserve water and concentrate the urine. In diabetes insipidus this signal fails – either because too little of the hormone is made, or because the kidneys do not respond to it. As a result, the kidneys pass large amounts of dilute, pale urine, and the person becomes very thirsty as the body tries to replace the lost fluid. It is unrelated to blood sugar despite the shared name, which is why doctors increasingly use the clearer terms arginine vasopressin deficiency (for the brain-related form) and arginine vasopressin resistance (for the kidney-related form).
Symptoms
The main symptoms are passing large amounts of pale, watery urine and needing to urinate very often, including waking through the night to pass water. This is paired with intense thirst, often with a strong preference for cold water. Some people find that constantly drinking and passing urine disrupts their sleep, work and daily life. In children, the condition may show up as bedwetting, poor growth, feeding difficulties or irritability. If fluids are not kept up – for example during illness, hot weather or when water is hard to reach – there is a real risk of dehydration, which can become serious.
Types in plain terms
There are two main forms. In the cranial (central) type, the body does not make enough vasopressin because of a problem in the pituitary gland or the brain. In the nephrogenic type, the body makes the hormone but the kidneys do not respond to it properly. The two forms share similar symptoms but have different causes and treatments, so telling them apart is an important part of the assessment.
Causes and who is at risk
The central type can follow anything that affects the pituitary gland or nearby brain tissue – for example a pituitary or brain tumour, surgery in that area, a head injury, or inflammation. Sometimes no cause is found. The kidney (nephrogenic) type can be inherited and present from early childhood, or it can develop later in life because of certain long-term medicines or an imbalance in the body’s salts. Because the causes are so varied, part of the specialist’s job is to look for and treat any underlying condition.
How it is diagnosed
Diagnosis is made by an endocrinologist and usually involves blood and urine tests to look at how dilute the urine is and how the body’s salts are balanced. A carefully supervised water-deprivation test may be arranged, in which fluid intake is monitored under close medical supervision to see how well the body concentrates its urine, sometimes together with a trial dose of the hormone-replacement medicine to tell the central and kidney types apart. If a brain or pituitary cause is suspected, an MRI scan of the pituitary and brain may be requested. This testing is done in hospital settings such as SGH or NUH so that fluid balance can be watched safely.
Treatment
Treatment depends on the type. For the central form, the missing hormone is replaced with the hormone-replacement medicine, which reduces the excessive urine and thirst; the endocrinologist adjusts it carefully to avoid holding on to too much water. For the kidney form, the focus is on treating any underlying cause, dietary measures guided by the care team, and specific medicines that help the kidneys manage water. In all forms, ensuring free and reliable access to water is essential, because the body still relies on drinking to replace the fluid it loses.
Living with it and self-care
Most people manage well with the right treatment and sensible habits. Keep water within reach at home, at work and when travelling. Carry medical alert information – such as a card or bracelet – so that others know about the condition in an emergency. Take extra care during illness, especially with vomiting, diarrhoea or fever, and during hot weather or long journeys when access to water may be limited, as these situations raise the risk of dehydration. If you take the hormone-replacement medicine, follow your endocrinologist’s advice closely and attend follow-up appointments so your treatment stays properly balanced.
When to seek urgent help
Seek urgent medical care if you notice signs of dehydration – extreme thirst that cannot be satisfied, confusion, dizziness, feeling very unwell, or being unable to take in enough fluid. In a child, warning signs include drowsiness, floppiness, sunken appearance and very few wet nappies. If you or your child are very unwell, cannot keep up with fluids, or become confused or difficult to rouse, call 995 or go to the nearest A&E immediately.
Common questions
Is this the same as diabetes (sugar diabetes)?
No. Diabetes insipidus is a water-balance disorder caused by a hormone problem and has nothing to do with blood sugar or insulin. Sugar diabetes (diabetes mellitus) is a completely different condition. The two only share part of their name for historical reasons.
Why do I feel so thirsty and pass so much urine?
Because the signal that tells the kidneys to conserve water is not working, the kidneys let too much water out as dilute urine, and thirst is the body’s way of trying to replace it.
Can it be cured?
It is usually a long-term condition, but it can be managed very effectively. Where there is a treatable underlying cause, addressing that may improve the situation.
Is it dangerous?
With treatment and good access to water, most people stay well. The main risk is dehydration if fluids cannot be kept up, which is why the warning signs above matter.
Which doctor should I see in Singapore?
An endocrinologist, at a hospital such as SGH or NUH, is the specialist who diagnoses and manages diabetes insipidus.
Related guides
Sources
- Singapore General Hospital
- HealthHub
- Society for Endocrinology
- NHS
Disclaimer: This guide is for general information only and does not replace personal medical advice. Always consult a qualified doctor about your own health. In an emergency, or if you or your child are very unwell or unable to keep up with fluids, call 995 or go to the nearest A&E.